A HSA used for a HDD includes: a flexible-printed-circuit (FPC) board for transmitting a write signal and read-back signal; an arm-electronics (AE) module, for performing amplification and waveform shaping of a write signal and a read-back signal; a lead-suspension for supporting a magnetic-recording head, and for transmitting a write signal and read-back signal between the AE module and the magnetic-recording head; an actuator arm for supporting such components; and, a coil for rotating the actuator arm for performing positioning of the magnetic-recording head in accessing data on a magnetic-recording disk. In addition, the HSA provides for transmitting the write signal and the read-back signal between the magnetic-recording head and a signal-processing unit, which may be fabricated as a large-scale integrated (LSI) circuit, disposed outside a disk enclosure (DE) of the HDD. As described herein, an AE module may also be referred to as a recording/reproducing integrated circuit (IC); and, a write signal and a read-back signal, may also be referred to as a recording signal and a reproducing signal, respectively.
In addition, as is known in the art, a metal layer may be disposed on the FPC board, which is one of components forming a signal transmission system for transmitting the write signal and the read-back signal, to control characteristic impedance so as to provide characteristic impedance matching between the components of the signal transmission system. Thus, reflection of a signal is reduced, so that degradation of a write signal and read-back signal may be prevented, as is known in the art.
As is also known in the art, a concave portion may be disposed in a surface of a metal plate in contact with an actuator arm, and a convex portion of the FPC board may be disposed in a surface of the actuator arm in contact with the metal plate, so that contact area of the metal plate to the actuator arm is increased. Thus, heat generated by the AE module may be efficiently transferred to the actuator arm, or alternatively, a DE, through the FPC board and the metal plate.
Moreover, as is known in the art, write-signal transmission lines on a lead-suspension may be divided into three blocks; characteristic impedance of each block may be individually set; and, a relationship in magnitudes of characteristic impedances between the blocks may be specified. Thus, a suitable write signal may be obtained by using a reflected wave caused by characteristic impedance mismatching.
Engineers and scientists engaged in HDD manufacturing and development are interested in the design of HDD components, such as, the HSA, that affect signal quality and ultimately affect HDD performance to meet the rising demands of the marketplace for increased reliability and performance.